'99 & up 7.3L Power Stroke Engine and DrivetrainDiscussion of the 99 & up 7.3L Power Stroke diesel engine and drivetrain in the 1999-Up Super Duty trucks and Excursions. No gas engine discussion allowed except on transmissions and drivetrain that pertain to all models. Please confine discussion of topics in this forum to those items that are specific to the 7.3L Power Stroke engine.

I have a 2001 F250 4WD with the 4R100 automatic transmission with 69,000 miles. I run the Diablo Predator 85HP tune with firm shift points. In April I noticed the truck shifting rough from 1-2 and 2-3, slipping, having a rough high idle, and the Overdrive light flashing. The truck also completely shut off in traffic.

I reset the codes and did not have a problem for a month, but I also rarely drive the truck.

Today I experienced the same problems shifting, slipping, and overdrive flashing. In addition to the codes above, I also have
P0720 Output Shaft Speed Sensor Circuit.

I have a call in to the Ford Dealer, but am interested to see if anyone can help diagnose and provide recommendations. The Ford dealer wants $735 in labor alone and recommends an overhaul or rebuild, but will get back to me with better estimates.

If I need to put in a new transmission, what are the thoughts about the ATS or other? Any recommendations for a good transmission shop in Northern Virginia?

No
REPEAT procedure to ENTER PID. If vehicle did not enter PID, REFER to Powertrain Control/Emissions Diagnosis (PC/ED) manual ( OBDII Early release , OBDII-Diesel , OBDII-Bi-Fuel ) for diagnosis of PCM.
F2 DRIVE CYCLE TEST
While monitoring the appropriate sensor PID, drive the vehicle so that the transmission upshifts and downshifts through all gears.

Does the TSS, or OSS Speed PID increase and decrease with engine and vehicle speed or is the sensor signal erratic (drop to zero or near zero and return to normal operation)?
Yes
If the TSS or OSS Speed PID increase and decrease with engine and vehicle speed, CLEAR all DTCs. ROAD TEST to verify if concern is still present. If concern is still present, REFER to Diagnosis By Symptom in this section for diagnosis.

If the sensor signal is erratic, INSPECT for intermittent concern in the internal/external harness, sensor or connector.

No
If the TSS, or OSS Speed PID does not increase and decrease with engine and vehicle speed, INSPECT for open or short in vehicle harness, sensor, a PCM concern, or internal hardware concern.

If the sensor signal is steady, GO to F3 .
F3 CHECK RESISTANCE OF TSS OR OSS SENSOR
Disconnect the appropriate vehicle harness connector from the TSS and or OSS sensor.

For TSS or OSS: Measure the resistance between pin 1 and pin 2 at the sensor. Record the resistance. Resistance should be as follows: Sensor Resistance (ohms) TSS — PTO Only Applications 496-1,244 TSS — Non-PTO Applications 781-1,979 OSS — All Applications 781-1,979

Is the resistance within specification for the appropriate sensor? Yes REFER to Diagnosis By Symptom in this section for concern diagnosis.

No
REPEAT procedure to ENTER PID. If vehicle did not enter PID, REFER to Powertrain Control/Emissions Diagnosis (PC/ED) manual ( OBDII Early release , OBDII-Diesel , OBDII-Bi-Fuel ) for diagnosis of PCM.
F2 DRIVE CYCLE TEST
While monitoring the appropriate sensor PID, drive the vehicle so that the transmission upshifts and downshifts through all gears.

Does the TSS, or OSS Speed PID increase and decrease with engine and vehicle speed or is the sensor signal erratic (drop to zero or near zero and return to normal operation)?
Yes
If the TSS or OSS Speed PID increase and decrease with engine and vehicle speed, CLEAR all DTCs. ROAD TEST to verify if concern is still present. If concern is still present, REFER to Diagnosis By Symptom in this section for diagnosis.

If the sensor signal is erratic, INSPECT for intermittent concern in the internal/external harness, sensor or connector.

No
If the TSS, or OSS Speed PID does not increase and decrease with engine and vehicle speed, INSPECT for open or short in vehicle harness, sensor, a PCM concern, or internal hardware concern.

If the sensor signal is steady, GO to F3 .
F3 CHECK RESISTANCE OF TSS OR OSS SENSOR
Disconnect the appropriate vehicle harness connector from the TSS and or OSS sensor.

For TSS or OSS: Measure the resistance between pin 1 and pin 2 at the sensor. Record the resistance. Resistance should be as follows: Sensor Resistance (ohms) TSS  PTO Only Applications 496-1,244 TSS  Non-PTO Applications 781-1,979 OSS  All Applications 781-1,979

Is the resistance within specification for the appropriate sensor? Yes REFER to Diagnosis By Symptom in this section for concern diagnosis.

No For TSS and OSS, INSTALL a new sensor.

Thanks - I cleared all the codes and drove the truck again this weekend. and the same thing happened. I am getting the VSS and OSS trouble codes. Does anyone have the part # for the OSS? I'll check the resistance on both sensors and see what I find out.

The attached pdf has pictures and part #'s for the E4OD and 4R100. It might be of use to someone else out there too. I think the VSS/OSS part # is F81Z-7M101-AA

Update: I ended up having the alternator replaced. When they ran a diagnostic check on the truck, the computer indicated the truck was going 30-70 MPH while sitting still. While I did replace the OSS, that was not the culprit. There was some sort of RF interference from the alternator.

While I replaced the alternator, this did not solve the poroblem. I eventually isolated the problem to a loose solenoid connection on the passenger side fender well. It was loose and after I tightened it I have had absolutley no issues.

Register Now

In order to be able to post messages on the Diesel Forum - TheDieselStop.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:

Password

Please enter a password for your user account. Note that passwords are case-sensitive.

Password:

Confirm Password:

Email Address

Please enter a valid email address for yourself.

Email Address:

Log-in

User Name

Remember Me?

Password

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

The AutoGuide.com network consists of the largest network of enthusiast-owned enthusiast-operated automotive communities.

AutoGuide.com provides the latest car reviews, auto show coverage, new car prices, and automotive news. The AutoGuide network operates more than 100 automotive forums where our users consult peers for shopping information and advice, and share opinions as a community.